William is the billionaire brother of Charles and David Koch and one the four sons of Fred Koch, founder of Koch Industries. Unlike his conservative-leaning brothers, Koch has given money to candidates on both sides of the aisle, supporting politicians who back his energy interests.

His cash has helped fund the campaigns of Democrats such as the late Massachusetts Sen. Ted Kennedy, former Vice President Al Gore and former Sen. Hillary Rodham Clinton, as well as Republican Sens. Marco Rubio of Florida and John McCain of Arizona and House Speaker John Boehner of Ohio.

He sold his share of the family business for a reported $1.3 billion in 1983 after a failed takeover bid and later sued for more, accusing Koch Industries of stealing oil from federal land. In 2001, the company settled the lawsuit for $25 million, CBS News reported.

Koch struck out on his own and formed Oxbow, an energy development company based in Palm Beach, Fla. A chemical engineer, Koch earned bachelor’s, master’s and doctoral degrees from the Massachusetts Institute of Technology, and with Oxbow, he made his fortune in energy commodities.

The corporation mines, sells and trades coal, natural gas and calcined coke, an ingredient used in the production of aluminum. Last year, Oxbow was ranked as the 91st largest private company in the country, according to Forbes, and has a reported $1.7 billion in combined assets.

Oxbow has lobbied on emissions standards, including regulations on greenhouse gases and this year’s highway bill, which passed in June after provisions on the Keystone XL oil pipeline and coal ash regulation were dropped. Oxbow has also poured money into support for Koch’s Central Rockies Land Exchange bill which, if passed, would give him a tract of land that bisects his Colorado ranch.

Koch is a big fan of the Wild West. He even has the ghost town to prove it. In 2010, he dropped $3.1 million to buy Buckskin Joe, a fake ghost town and Old West tourist attraction in Colorado. He moved the buildings, which once served as the background for classic cowboy movies, to his 5,000-acre ranch. Last year, he spent $2.3 million to win an auction for the world’s only photograph of Billy the Kid, CNN reported.

When he’s not playing sheriff, Koch is also an avid sailor. He won the 1992 America's Cup with his yacht, America. The Boy Scouts of America hosts the William I. Koch International Sea Scout Cup in his honor.

Last updated: Jan. 30, 2013

*2011-2012 election cycle. Source: Center for Responsive Politics and Center for Public Integrity analysis of Federal Election Commission records. Totals include contributions from individuals, family members and corporations that are controlled by the individual super donor.